The invention described below relates to chromatography and, more particularly, to chromatography systems and methods of configuring and operating such chromatography systems for improving the separation of various components found within a composition.
Chromatography generally involves the use of one or more solvents to separate a sample composition of multiple components into individual components as a result of the solvents and the sample composition flowing around, over, or through a stationary liquid or solid phase. Different mechanisms and/or techniques may be used to perform different types of chromatography. For example, thin layer chromatography (TLC) generally involves the use of a vessel containing a solvent or solvent system and a chromatography plate (“the plate”) that includes a thin layer of silica or other suitable material. In conventional TLC, a sample composition is applied to a lower portion of the plate and a lower edge of the plate is immersed in a solvent composition. The plate is then maintained in a generally vertical orientation so that over time the solvent will move, via capillary action, upwardly through the layer of material provided on the surface of the plate. As the solvent moves past the sample composition, one or more of the components within the sample will be dissolved and carried along with the solvent upwardly along the surface of the plate. The various components will be moved by the solvent at different rates, thereby tending to separate a plurality of components across the surface of the TLC plate.
Based on the relative distances between the movement of the solvent front, LSF, and the movement of the various dissolved components A, B . . . N that were present in the sample composition, LCA, LCB . . . LCN, across the plate within a given period of time, a corresponding retention factor (Rf) may be calculated for each of the separated or distinguishable components. The Rf represents the ratio of the distance traveled by a component present in the sample and the solvent. For example, if component A of a sample is moved a distance LCA by a solvent that traveled a distance LSF along the plate at the same time, the Rf for component A may be calculated using equation 1:LCA/LSF=RfA  (1).
Because various chromatographic techniques provide different combinations of advantages and disadvantages, those skilled in the art of chromatography may use multiple chromatographic techniques and/or methods in order to achieve an acceptable separation of the components within a single sample composition. However, the separation conditions that produce acceptable results for one chromatographic method may not, and commonly will not, produce acceptable results if transferred directly to another chromatographic method. Accordingly, the process of adapting the separation conditions used in one type of chromatography to another type of chromatography has continued to challenge those skilled in the art and typically requires additional experimentation to adapt the initial separation conditions in order to achieve satisfactory results.
Although various methods, approaches and techniques have been developed for use in such efforts and have proved helpful to chemists, pharmacists and others who practice such chromatography, a significant degree of operator involvement remains in most instances. As will be appreciated by those skilled in the art, the degree of operator involvement, including, for example, calculations and “guess and check” trials for improving the separation of a particular group of components may be increased when dealing with unknown components and/or components that exhibit similar Rf values in conventional solvent systems.